Net-zero emission targets for major emitting countries consistent with the Paris Agreement

Area of Science:

• Climate Science
• Environmental Policy
• Integrated Assessment Modeling

Background:

• Many nations are setting net-zero emissions targets, but these are often global averages.
• Understanding national-level emissions neutrality timelines is crucial for effective climate policy.

Purpose of the Study:

• To determine national-level net-zero greenhouse gas and CO2 emissions targets.
• To analyze these targets based on cost-effective 1.5°C and 2°C global climate scenarios.
• To compare model-based targets with equity-based approaches.

Main Methods:

• Utilizing integrated assessment models to simulate globally cost-effective climate scenarios.
• Analyzing national-level emissions neutrality years, considering land-use emissions.
• Comparing projected phase-out years based on factors like carbon storage capacity, income, and non-CO2 emissions.

Main Results:

• Brazil and the USA are projected to reach domestic net-zero emissions a decade earlier than the global average.
• India and Indonesia are projected to reach net-zero emissions later than the global average.
• National variations in neutrality years are influenced by land-use accounting, afforestation capacity, income, non-CO2 emissions, and transport sector emissions.

Conclusions:

• National net-zero targets vary significantly based on country-specific factors and modeling choices.
• Integrated assessment models provide valuable insights into national emissions phase-out timelines.
• Results can inform policymakers in setting realistic and equitable net-zero targets.